Editing 20110105 Lecture 4 notes.txt
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===Mechanism of phototransduction=== | ===Mechanism of phototransduction=== | ||
*Our photoreceptors are still secreting NT even when asleep because they are depolarized. | *Our photoreceptors are still secreting NT even when asleep because they are depolarized. | ||
- | **They are depolarized because the inner segment is secreting cGMP which | + | **They are depolarized because the inner segment is secreting cGMP which activate cGMP-gated non-selective cation channel (Na |
+ | |||
+ | and Ca influxing). | ||
*Our voltage is not zero, however, because of K+ channels that move K+ outward (effluxing). | *Our voltage is not zero, however, because of K+ channels that move K+ outward (effluxing). | ||
- | **This will generate hyperpolarization (because we are asleep and we are effluxing more K+ than influxing Na and Ca+ so the voltage is becoming more negative). | + | **This will generate hyperpolarization (because we are asleep and we are effluxing more K+ than influxing Na and Ca+ so the |
- | * | + | |
- | + | voltage is becoming more negative). | |
+ | *Deem = dim. :) | ||
===Visual transduction=== | ===Visual transduction=== |